Correlation of ZAP-70 expression with IgV_H mutational status. Sixty-five percent of patients with mutated IgV_H gene were ZAP-70^– as assessed by flow cytometry and 100% of patients with unmutated IgVH genes were ZAP-70⁺. Twenty-six percent of patients were ZAP-70⁺ and mutated, of these patients the majority had additional bad prognostic markers (ie, CD38 positivity or unfavorable IgV_H gene usage; Table 1).